In reply to Rick Wicklin.

Thank you, Rick.

Martin, R (Clin Chem, 46:1, 100-104, 2000) has developed the confidence band for the Bias (Bc) of Y at Xc, Bc=a+Xc(b-1); CI=Bc +/- t(alpha/2, n-2).SE(Bc). I think this approach should be applicable to Yhat as well. It surprised me that df=n-2.
I haven't yet found literature for the prediction band either other than that in CLSI EP14.
CLSI EP14 does have a methodology for Deming prediction band, including an adjustment for the number of measurements associated with each (X, Y) pair.
This is important, in analytical method comparison studies, it is typical to call for 1+ measurements for each specimen in each method. EP9 calls for 2, EP14 for 2+.